Why we should consider making the coronavirus tracking app opt-out

April 28 2020

Hugh headshot 2

Emeritus Professor Hugh Bradlow FTSE

President, Australian Academy of Technology and Engineering

Notwithstanding suspicion of opt-out data systems, the Australian government’s coronavirus track and trace app has merit.

Such a system would give earlier opportunities to isolate potential infections and also provide more accurate prediction models.

A key issue, demonstrated by the My Health Record rollout, is that for the system to be effective, the number of people opting in needs to be widespread. So, if we want an effective way to track and trace the spread of the coronavirus, there is valid argument for making the app mandatory, which would require everyone who has a smartphone (~84 per cent of the Australian population) to opt-in.

However, if we look at why people don’t opt into these data systems, the deepest concerns relate to the privacy and potential misuse of personal information.

Privacy concerns are absolutely valid. However, the app being suggested (assuming it is based on the technology that Apple and Google will build into their phones – which we can’t confirm until they publish the source code) does not enable for the government or anyone else to track where you have been or with whom you have been in contact with. So, you ask, how can that be if the app is able to determine when you have been close to an infected person?

The answer is in the form of a very clever system of identifiers which for people who have not tested positive will never be uploaded to the cloud. Every 10 minutes, a smartphone records “identifiers”(which are anonymous through sophisticated encryption) of other smartphones that were in Bluetooth range (about 3m to 10m).

Should someone be diagnosed positive with the virus, then a series of their smartphone identifiers (probably for the last month) are uploaded to the cloud so that yours and everyone else’s app can see if you (or your smartphone) have been in proximity of an infected person.

It is important to note that these identifiers are in no way personally identifiable to you or other people, and they change from day to day. The only data that anyone can see (including the government) is the list of identifiers for each day of the smartphones of people who were infected. Again, these identifiers are independent of personal information.

There is no way to find out which individual each identifier is associated with. This has been verified by top security experts.

If the number of people with the virus declines dramatically (a most desirable state) and the list of people with the virus is very short (e.g. only one person) then knowing who has a diagnosis would enable that person to be identified.

However, there is still no way for the government (or anyone else) to know who they have been in contact with. That information is held on individual phones and not uploaded to the cloud.

So, would a track and trace app effectively help to curb the spread of the coronavirus? I am not an epidemiologist so I do not have the expertise to judge this. However, a track and trace app would clearly be more effective than doing nothing.

Only by ensuring enough people are using the app, will we be able to collect the data to answer this particular question definitively. There is no reason not to consider making the app a required opt-out.

Hugh Bradlow headshot
Emeritus Professor Hugh Bradlow FTSE

Professor Bradlow is President of the Australian Academy of Technology and Engineering. He is also an independent Non-Executive Director of Silicon Quantum Computing Pty Ltd.

He was previously Chief Technology Officer and Head of Innovation at Telstra, responsible for the R&D of new technologies and their introduction into Telstra’s business. Subsequently he became Chief Scientist at Telstra, in which role he advised the Telstra Board and management on the longer term technology directions and technology disruption anticipated to impact Telstra and its customers.



He is globally recognised as a thought leader in telecommunications and was elected as the joint 2009 Australian Telecommunications Ambassador of the Year, named by Global Telecom Business as one of the most 100 most influential telecommunications executives in the world and designated as one of the 12 most influential people in Australian ICT by Smart Company.